cleanup code

VRCXStorage.cs

@@ -12,7 +12,7 @@ namespace VRCX
 {
     public class VRCXStorage
     {
-        public static VRCXStorage Instance { get; private set; }
+        public static readonly VRCXStorage Instance;
         private static readonly ReaderWriterLockSlim m_Lock = new ReaderWriterLockSlim();
         private static Dictionary<string, string> m_Storage = new Dictionary<string, string>();
         private static string m_JsonPath = Path.Combine(Program.BaseDirectory, "VRCX.json");